Abstract: The gas quality of natural gas entering the long-distance pipeline network shall meet the requirements of H₂S mass concentration no more than 6 mg/m³, CO₂ molar fraction no more than 3%, and total sulfur mass concentration no more than 20 mg/m³ in GB 17820-2018 Natural Gas. In order to meet the requirements of GB 17820-2018, the original MDEA desulfurization solution of three purification plants of PetroChina Southwest Oil and Gasfield Company has been upgraded to organic sulfur removal solvent CT8-24. The organic sulfur removal solvent is different from conventional MDEA chemical solvent. It belongs to physical-chemical solvent, which can remove organic sulfur both by physical dissolution and chemical absorption. Therefore, the influence of process parameters on organic sulfur removal is more complex. The factors affecting the removal of organic sulfur were studied in laboratory and purification plant respectively, including absorption pressure, gas-liquid ratio and gas-liquid contact time, etc. The effects of various factors on the removal rate of organic sulfur were systematically analyzed. The results showed that high absorption pressure, low gas-liquid ratio and long gas-liquid contact time were favorable to the deep removal of organic sulfur. It provides a technical reference for optimizing the unit operation and the gas quality of other natural gas purification plants up to standard.